Bio-Inspired Screwed Conduits from the Microfluidic Rope-Coiling Effect for Microvessels and Bronchioles

Tubular microfibers have recently attracted extensive interest for applications in tissue engineering.However,the fabrication of tubular fibers with intricate hierarchical structures remains a major challenge.Here,we present a novel one-step microfluidic spinning method to generate bio-inspired screwed conduits(BSCs).Based on the microfluidic rope-coiling effect,a viscous hydrogel precursor is first curved into a helix stream in the channel,and then consecutively packed as a hollow structured stream and gelated into a screwed conduit(SC)via ionic and covalent crosslinking.By taking advantage of the excellent fluid-controlling ability of microfluidics,various tubes with diverse structures are fabricated via simple control over fluid velocities and multiple microfluidic device designs.The perfusability and permeability results,as well as the encapsulation and culture of human umbilical vein endothelial cells(HUVECs),human pulmonary alveolar epithelial cells(HPAs),and myogenic cells(C2C12),demonstrate that these SCs have good perfusability and permeability and the ability to induce the formation of functional biostructures.These features support the uniqueness and potential applications of these BSCs as biomimetic blood vessels and bronchiole tissues in combination with tissue microstructures,with likely application possibilities in biomedical engineering.

Observation of Arctic surface currents using data from a surface drifting buoy

During the 10th Chinese Arctic scientific expedition carried out in the summer of 2019,the surface current in the high-latitude areas of the Arctic Ocean was observed using a self-developed surface drifting buoy,which was initially deployed in the Chukchi Sea.The buoy traversed the Chukchi Sea,Chukchi Abyssal Plain,Mendeleev Ridge,Makarov Basin,and Canada Basin over a period of 632 d.After returning to the Mendeleev Ridge,it continued to drift toward the pole.Overall,the track of the buoy reflected the characteristics of the transpolar drift and Chukchi Slope Current,as well as the inertial flow,cross-ridge surface flow,and even the surface disorganized flow for some time intervals.The results showed that:(1)the transpolar drift mainly occurs in the Chukchi Abyssal Plain,Mendeleev Ridge,and western Canada Basin to the east of the ridge where sea ice concentration is high,and the average northward flow velocity in the region between 79.41°N and 86.32°N was 5.1 cm/s;(2)the average surface velocity of the Chukchi Slope Current was 13.5 cm/s,and while this current moves westward along the continental slope,it also extends northwestward across the continental slope and flows to the deep sea;and(3)when sea ice concentration was less than 50%,the inertial flow was more significant(the maximum observed inertial flow was 26 cm/s,and the radius of the inertia circle was 3.6 km).

Underwater image clarifying based on human visual colour constancy using double-opponency

Underwater images are often with biased colours and reduced contrast because of the absorption and scattering effects when light propagates in water.Such images with degradation cannot meet the needs of underwater operations.The main problem in classic underwater image restoration or enhancement methods is that they consume long calcu-lation time,and often,the colour or contrast of the result images is still unsatisfied.Instead of using the complicated physical model of underwater imaging degradation,we propose a new method to deal with underwater images by imitating the colour constancy mechanism of human vision using double-opponency.Firstly,the original image is converted to the LMS space.Then the signals are linearly combined,and Gaussian convolutions are per-formed to imitate the function of receptive fields(RFs).Next,two RFs with different sizes work together to constitute the double-opponency response.Finally,the underwater light is estimated to correct the colours in the image.Further contrast stretching on the luminance is optional.Experiments show that the proposed method can obtain clarified underwater images with higher quality than before,and it spends significantly less time cost compared to other previously published typical methods.

3D Bioprinting for Biomedical Applications

Three-dimensional(3D)printing,referring to a type of additive manufacturing,has emerged as a promising fabrication technique in the past decades since it can create 3D objects with desired architecture by precise control over the deposition of successive layers of various materials.Benefiting from these advantages,3D printing has been extensively applied in varied areas of science and engineering.

Plasma free amino acid profiling of esophageal cancer using high-performance liquid chromatography spectroscopy

AIM: To perform plasma free amino acid (PFAA) profiling of esophageal squamous cell carcinoma (ESCC) patients at different pathological stages and healthy subjects.

Acellular ostrich corneal stroma used as scaffold for construction of tissue-engineered cornea

AIM： To assess acellular ostrich corneal matrix used as a scaffold to reconstruct a damaged cornea. METHODS： A hypertonic saline solution combined with a digestion method was used to decellularize the ostrich cornea. The microstructure of the acellular corneal matrix was observed by transmission electron microscopy （TEM） and hematoxylin and eosin （H＆E） staining. The mechanical properties were detected by a rheometer and a tension machine. The acellular corneal matrix was also transplanted into a rabbit cornea and cytokeratin 3 was used to check the immune phenotype, RESULTS： The microstructure and mechanical properties of the ostrich cornea were well preserved after the decellularization process, in vitro, the methyl thiazolyl tetrazoUum results revealed that extracts of the acellular ostrich corneas （AOCs） had no inhibitory effects on the proliferation of the corneal epithelial or endothelial cells or on the keratocytes, The rabbit lamellar keratoplasty showed that the transplanted AOCs were transparent and completely incorporated into the host cornea while corneal turbidity and graft dissolution occurred in the acellular porcine cornea （APC） transplantation, The phenotype of the reconstructed cornea was similar to a normal rabbit cornea with a high expression of cytokeratin 3 in the superficial epithelial cell layer, CONCLUSION： We first used AOCs as scaffolds to reconstruct damaged corneas. Compared with porcine corneas, the anatomical structures of ostrich corneas are closer to those of human corneas. In accordance with the principle that structure determines function, a xenograft lamellar keratoplasty also confirmed that the AOC transplantation generated a superior outcome compared to that of the APC graft.

A retrospective analysis of the safety and efficacy of apatinib in treating advanced metastatic colorectal cancer

Objective Colorectal cancer(CRC) is a heterogeneous disease in which both epigenetic alterations and gene mutations transform normal cells into cancer cells. Apart from a variety of standard treatments, there are few options available to improve a CRC patient's overall survival(OS) and quality of a life. The objective of the present retrospective study was to analyze the response and toxicity associated with apatinib in patients with metastatic CRC(m CRC).Method Data on the use of apatinib as salvage therapy were collected from patients diagnosed with m CRC, Eastern Cooperative Oncology Group(ECOG) performance status ≤ 3, from the Luhe Hospital. A total of 17 patients with stage IV unresectable m CRC, who received at least one cycle of apatinib, between October 2015 and February 2017, were involved in this study. Our primary endpoints were the overall response rate(ORR) and disease control rate(DCR), and the secondary objectives were progression-free survival(PFS), OS and safety.Result Seventeen patients with a median age of 62 years(34–83 years) were enrolled. Twelve patients were male, and the location of the primary tumor was in the colon and the rectum in 9 and 8 patients, respectively. Liver metastasis was observed in 9 patients and lung metastasis in 5. The ECOG performance status was 0 to 2 in 13 patients. The ORR at the first evaluation was 17.6 %(3/17). The DCR was 82.4%(14/17). The median PFS was 3.0 months(95% confidence interval(CI): 1.924–4.076 months) and the median OS was 5.4 months(95% CI: 3.383–7.417 months). Grade 1–2 adverse events included hypertension(52.9%), fatigue(64.7%), anorexia(29.4%), hoarseness(23.5%), proteinuria(23.5%), and development of rashes(17.6%). Grade 3 adverse events included thrombocytopenia(5.9%) and proteinuria(5.9%). There were no Grade 4 adverse events in our analysis.Conclusions Apatinib was found to be both safe and effective in the treatment of advanced m CRC, and its associated toxicities were acceptable and manageable. However, further studies are required to validate these findings.

Monitoring the hydrolyzation of aspirin during the dissolution testing for aspirin delayed-release tablets with a fiber-optic dissolution system

The purpose of this study was to investigate the hydrolyzation of aspirin during the process of dissolution testing for aspirin delayed-release tablets. Hydrolysis product of salicylic acid can result in adverse effects and affect the determination of dissolution rate assaying. In this study, the technique of differential spectra was employed, which made it possible to monitor the dissolution testing in situ. The results showed that the hydrolyzation of aspirin made the percentage of salicylic acid exceed the limit of free salicylic acid （4.0）, and the hydrolyzation may affect the quality detection of aspirin delayed-release tablets.

Effects of temperature and wavelength choice on in-situ dissolution test of Cimetidine tablets

The effects of temperature and wavelength choice on in-situ dissolution test instrument of Cimetidine were studied. Absorbance （A）〈 1.0 is required when using a fiber-optic dissolution test system. The detection wavelength of 2 （218 nm） was replaced by 244 nm to carry out this test. The absorbance of Cimetidine solution at different temperature showed an obvious change. Calibration of Cimetidine solution should be tested at the same temperature （37° C） with the test solution. A suitable wavelength with smaller tangent slope could be chosen for in-situ dissolution test of Cimetidine tablets.

Multi-Scale Fusion Algorithm for AUVs Integrated Navigation Systems

To deal with the low location accuracy issue of existing underwater navigation technologies in autonomous underwater vehicles(AUVs),a distributed fusion algorithm which combines the model's analysis method with a multi-scale transformation method is proposed for integrated navigation system based on AUV.First,integrated navigation system theory and system error sources are introduced in details.Secondly,a navigation system's observation equation on the original scale is decomposed into different scales by the discrete wavelet transform method,and noise reduction is performed by setting the wavelet de-noising threshold.At last,the dynamic equation and observation equations are fused on different scales by the wavelet transformation and Kalman filter.The results show that the proposed algorithm has smaller navigation error and higher navigation accuracy.

Microstructure and room temperature fracture toughness of Nb-Si-based alloys with Sr addition

Nb-Si-based alloys show great potential to surpass the widely used Ni-based superalloys.The element Sr is widely applied in aluminum and magnesium alloys,but reports about the effects of Sr on Nb-Si-based alloys are quite rare.So,Nb-Si-based alloys with nominal compositions of Nb-15Si-24Ti-4Cr-2Al-2Hf-0/0.05/0.15Sr(at%)were prepared by directional solidification and heat treatment.The microstructural characterization and room temperature fracture toughness of Nb-Si-based alloy were systematically investigated.Results show that all these alloys consist of Nb_5Si_3 phase embedded within Nb solid solution(Nb_(ss)) matrix.The Nb_(5)Si_(3) phase becomes refined and more discontinuous after adding minor Sr.As for the fracture toughness,0.05 at% and 0.15 at% Sr additions do not cause significant change.The discontinuous and refining mechanism of Sr element was studied,and the analysis of toughness decreasing with Sr addition reveals that the size of Nb_(ss) phase plays a crucial role in determining the fracture toughness.

Experimental and numerical studies on buckling and post-buckling behavior of T-stiffened variable stiffness panels

Currently,experimental research on variable stiffness design mainly focuses on laminates.To ensure adaptability in practical application,it is imperative to conduct a systematic study on stiffened variable stiffness structures,including design,manufacture,experiment,and simulation.Based on the minimum curvature radius and process schemes,two types of T-stiffened panels were designed and manufactured.Uniaxial compression tests have been carried out and the results indicate that the buckling load of variable stiffness specimens is increased by 26.0%,while the failure load is decreased by 19.6%.The influence mechanism of variable stiffness design on the buckling and failure behavior of T-stiffened panels was explicated by numerical analysis.The primary reason for the reduced strength is the significantly increased load bearing ratio of stiffeners.As experimental investigations of stiffened variable stiffness structures are very rare,this study can be considered a reference for future work.

Tailoring micro/nano-fibers for biomedical applications

Nano/micro fibers have evoked much attention of scientists and have been researched as cutting edge and hotspot in the area of fiber science in recent years due to the rapid development of various advanced manufacturing technologies,and the appearance of fascinating and special functions and properties,such as the enhanced mechanical strength,high surface area to volume ratio and special functionalities shown in the surface,triggered by the nano or micro-scale dimensions.In addition,these outstanding and special characteristics of the nano/micro fibers impart fiber-based materials with wide applications,such as environmental engineering,electronic and biomedical fields.This review mainly focuses on the recent development in the various nano/micro fibers fabrication strategies and corresponding applications in the biomedical fields,including tissue engineering scaffolds,drug delivery,wound healing,and biosensors.Moreover,the challenges for the fabrications and applications and future perspectives are presented.

Natural biopolymers derived hydrogels with injectable,self-healing,and tissue adhesive abilities for wound healing

Developing a biocompatible and multifunctional adhesive hydrogel with injectability and self-healing ability for promoting wound healing is highly anticipated in various clinical applications.In this paper,we present a novel natural biopolymer-derived hydrogel based on the aldehyde-modified oxidized guar gum(OGG)and the carboxymethyl chitosan(CMCS)for efficiently improving wound healing with the encapsulation of vascular endothelial growth factor(VEGF).As the hydrogels are synthesized via the dynamically reversible Schiff base linkages,it is imparted with excellent self-healing ability and good shear thinning behavior,which make the hydrogel be easily and conveniently injected through a needle.Besides,the physiochemical properties,including porous structure,mechanical strength and swelling ratio of the hydrogel can be well controlled by regulating the concentrations of the OGG.Moreover,the hydrogel can attain strong adhesion to the tissues at physiological temperature based on the Schiff base between the aldehyde group on the hydrogel and the amino group on the tissue.Based on these features,we have demonstrated that the VEGF encapsulated hydrogel can adhere tightly to the defect tissue and improve wound repair in the rat model of defected skin by promoting cell proliferation,angiogenesis,and collagen secretion.These results indicate that the multifunctional hydrogel is with great scientific significance and broad clinical application prospects.

Microstructures and high-temperature oxidation behavior of directionally solidified Nb-Si-based alloys with Re additions

High-temperature oxidation behavior of directionally solidified(DS) Nb-Si-based alloys with Re additions was investigated at 1200 and 1250℃,respectively.Microstructures and high-temperature oxidation behavior of the alloys were characterized.Results show that the microstructures in vertical section of Nb-24Ti-15Si-4Cr-2Al-2Hf-xRe(x=0,1,3;at%) alloys grow parallel to the withdrawal direction and the cross section exhibits bud-like structures.The bud-like structures become finer with more Re additions.The weight gain of the Nb-24Ti-15Si-4Cr-2Al-2Hf-3Re alloy after oxidation at 1200℃ for 100 h is 198.1 mg·cm^(-2),and it is a bit higher at 1250℃.The other two alloys perform somewhat worse.The influence of Re addition on the oxidation resistance at 1250℃ is more significant than that at 1200 ℃.Although Re addition does not benefit obviously the high-temperature oxidation resistance of the DS samples,it does not compromise the oxidation resistance with a certain amount of Re additions in contrast with the alloy without Re addition.

Fish scale-derived scaffolds with MSCs loading for photothermal therapy of bone defect

Tissue engineering scaffolds have presented effective value in bone repair.However,the integration of the diverse components,complex structures,multifunction to impart the scaffolds with improved applicability is still a challenge.Here,we propose a novel fish-derived scaffold combined with photothermal therapy and mesenchymal stem cells(MSCs)to promote bone regeneration.The fish-derived scaffold is composed of the decellularized fish scale and gelatin methacrylate synthesized from fish gelatin(fGelMA),which can promote the proliferation and osteogenesis of MSCs with no obvious immunological rejection.Furthermore,the black phosphorus(BP)nanosheets are incorporated into the fGelMA hydrogel network,which can endow the hydrogel with the capacity of photothermal conversion stimulated by near-infrared(NIR)light.The fish-derived scaffold can promote the osteogenesis process of MSCs with higher expression of osteogenic markers and higher mineralization assisted by the NIR light in vitro.The regeneration of mice calvarial defect has also been accelerated by the scaffold with photothermal therapy and MSCs.These results suggest that the fish-derived scaffold,photothermal therapy,MSCs-based regenerative therapy is a promising clinical strategy in bone regeneration.

Advances in antioxidative nanozymes for treating ischemic stroke

Ischemic stroke is one of the most common public diseases that increase mortality.In the ischemic brain,blood flow restoration can cause the generation of excess reactive oxygen species(ROS).Endogenous anti-oxidases in the living system,including catalase(CAT)and superoxide dismutase(SOD),can consume the excess ROS by catalysis to regulate inflammation.However,these natural enzymes are difficult to be widely used in the treatment of stroke.Taking advantages of high stability,low cost,and long-term storage,antioxidative nanozymes-mediated treatments have been proven as a promising method against ischemic stroke.To highlight the progress,we summarize the advances in nanozymes with the antioxidative ability for treating ischemic stroke.It is believed that such a promising therapeutic strategy of antioxidative nanozymes will significantly contribute to the field of ischemic stroke.We expect that antioxidative nanozymes will play significant roles in both basic research and clinical applications.

Chronic wounds:pathological characteristics and their stem cell-based therapies

Chronic wounds are characterized by prolonged healing processes and poor prognoses,which have substantially impacted human health and daily life.Traditional treatment strategies have various limitations and drawbacks.Therefore,fully effective therapeutic approaches remain urgently needed.Stem cell(SC)-based therapies have drawn significant attention for their abilities of immunomodulation and pro-regeneration.It has been demon-strated that stem cells(SCs)can improve angiogenesis,collagen deposition,and hair rejuvenation,thus facilitating wound healing.In addition,attempts were performed to facilitate the cell survival,function,retention,and en-graftment of the delivered SCs.In this review,we first introduce the pathological process involved in chronic wound healing.Following that,the mechanism of SCs in promoting chronic wound repair is discussed in detail.Then,we highlight recent SC-based therapies for chronic wound repair developments.Finally,we present our views on the remaining challenges and future trends of SC-based therapies for chronic wound treatment.

电强化使得针灸针功能更强大

Acupuncture,one of the major therapeutic methods of traditional Chinese medicine,is a treasure of traditional Chinese culture[1].Based on the theory of acupuncture points in meridians and channels,the therapeutic effect of acupuncture can be achieved by inserting the needles into the corresponding points,while“Ch’i”and“meridian”are the core of the acupuncture puzzle[2,3].

Biomimetic extracellular vesicles for the tumor targeted treatment

Extracellular vesicles(EVs)are nanoscale substances produced by most cells,which were not fully understood in the early years.However,with the development of advanced techniques,researchers have discovered that EVs play an essential role in information exchange and signal transduction between cells.Nowadays,EVs are being used,modified,and developed as a natural drug carrier in various medical fields because of their high biocompatibility and natural affinity with the source body.Many studies have shown that multiple sources of EVs have been modified and utilized in cancer therapy to improve patients’treatment windows and effectively prolong patient survival.In this paper,we review the advances in the treatment of cancer based on EVs.We summarize the types of EVs loading therapy,the modes of drug loading and the latest therapeutic applications of multiple modes combined with EVs in cancer treatment.We conclude with a discussion of the current status,challenges,and prospects of EVs as a tool for tumor therapy.